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Thread: SDS Grounding

  1. #11
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    Quote Originally Posted by ggunn View Post
    Yeah, the drawing is pretty fuzzy when I try to make it bigger. It sort of looks like one of the phases is bonded on both sides, but that can't be right.
    We touched on wye-wye recently in another thread, and although I have never really bought any of the reasons people throw out there, there seems to be thinking that bonding the two neutrals together is a good thing, hence why I jumped to the conclusion that they were intended to be bonded. Hopefully OP can clarify.
    Ethan Brush - East West Electric. NY, WA. MA

    "You can't generalize"

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    Quote Originally Posted by electrofelon View Post
    We touched on wye-wye recently in another thread, and although I have never really bought any of the reasons people throw out there, there seems to be thinking that bonding the two neutrals together is a good thing, hence why I jumped to the conclusion that they were intended to be bonded. Hopefully OP can clarify.
    If you see the PDF attached, I have bonded the neutral on both the sides because 250.30(A)(1)(b) says, "where the system bonding jumper is installed at the first disconnecting means of a separately derived system (T/F), the system bonding jumper must connect the neutral conductor of the derived system to the metal disconnecting means enclosure" - Mike Holt NEC 2014 Solar Photovoltaic Systems book.

    Which I interpreted as the first disconnecting means on both primary and secondary side.

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    Quote Originally Posted by TheElectrician View Post
    If you see the PDF attached, I have bonded the neutral on both the sides because 250.30(A)(1)(b) says, "where the system bonding jumper is installed at the first disconnecting means of a separately derived system (T/F), the system bonding jumper must connect the neutral conductor of the derived system to the metal disconnecting means enclosure" - Mike Holt NEC 2014 Solar Photovoltaic Systems book.

    Which I interpreted as the first disconnecting means on both primary and secondary side.
    You only bod N-G on the secondary side
    Ethan Brush - East West Electric. NY, WA. MA

    "You can't generalize"

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    Quote Originally Posted by TheElectrician View Post
    If you see the PDF attached, I have bonded the neutral on both the sides because 250.30(A)(1)(b) says, "where the system bonding jumper is installed at the first disconnecting means of a separately derived system (T/F), the system bonding jumper must connect the neutral conductor of the derived system to the metal disconnecting means enclosure" - Mike Holt NEC 2014 Solar Photovoltaic Systems book.

    Which I interpreted as the first disconnecting means on both primary and secondary side.
    The derived neutral is in the secondary of your transformer and there is no electrical connection to the primary unless you make one, and generally this is not done.
    If you don't think too good, don't think too much.

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    Quote Originally Posted by electrofelon View Post
    You only bod N-G on the secondary side

    It's correct that 250.30(A)(1) is only about the secondary side. But here's a loaded question:

    Is 89L a service disconnect? If so then the N-G bond there is correct.

    @TheElectrician
    We are not going to decide that question here, although you've got it drawn like it is a service disconnect. But you and the AHJ must be on the same page. Let us know if you need references to past threads on the forum.

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    Quote Originally Posted by TheElectrician View Post
    I have attached the pdf let me know if this gives a better idea.
    Why are you even running a neutral to the utility side of the transformer?

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    Quote Originally Posted by jaggedben View Post
    It's correct that 250.30(A)(1) is only about the secondary side. But here's a loaded question:

    Is 89L a service disconnect? If so then the N-G bond there is correct.
    Yes, but it depends on what OP meant by "bonded on the primary". I kinda took this to mean there was a N (primary)-G bond in the transformer, in addition to the bond at the service equipment. Maybe he was just talking about the Bond at the service...?
    Ethan Brush - East West Electric. NY, WA. MA

    "You can't generalize"

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    Quote Originally Posted by electrofelon View Post
    Yes, but it depends on what OP meant by "bonded on the primary". I kinda took this to mean there was a N (primary)-G bond in the transformer, in addition to the bond at the service equipment. Maybe he was just talking about the Bond at the service...?
    In his OP he said "I have bonded N-G on the first disconnecting means on both the primary and the secondary of the T/F to earth". I was making the point that while one doesn't bond the 'first disconnect' on the primary side, it just so happens that this 'first disconnect' likely needs it for other reasons.

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    Hey everyone, thanks for the useful comments, and I would like to clarify the confusion here about the bonding on the primary - what I meant here is that have a bond in the first disconnect on the primary side of the transformer (which is 89L in this case) and not inside the primary of the transformer.

    The updates I made to the drawing is, I bonded the N-G in the 89L, removed the bond in the 52IT and I have put a ground rod (Earth) in the 89L and the 52IT.

  10. #20
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    Quote Originally Posted by jaggedben View Post
    It's correct that 250.30(A)(1) is only about the secondary side. But here's a loaded question:

    Is 89L a service disconnect? If so then the N-G bond there is correct.

    @TheElectrician
    We are not going to decide that question here, although you've got it drawn like it is a service disconnect. But you and the AHJ must be on the same page. Let us know if you need references to past threads on the forum.
    Yes, it is a service disconnect here.

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